MJO forcing causes a heavy rain scenario across Northern Argentina/Paraguay and Northeast Brazil the next 7-10 days. However, tropical involvement is diminished in the extended range as Brazil shifts much drier. Dry soils in Southeast Brazil increase the risk of steady late season anomalous heat.

Neutral ENSO continues during early April as the Nino34 SSTA is unchanged at +0.2C. Last week, some warming was observed off the northwest coast of South America (Nino12). The subsurface upper ocean heat is MUCH warmer than normal and intensifying. The NEW Kelvin Wave features ocean temperatures 6-7C warmer than normal extending to just east of 150W and further eastward shifting is likely.

Suddenly, an immense Kelvin Wave has emerged just east of the Dateline in the equatorial Pacific Ocean likely to shift eastward during the next several weeks and accelerate upper ocean heat to fuel El Nino onset. The rate of expected warming is similar with the strongest El Nino’s on record in 2015 and 1997. Analogs and dynamic models are supportive of a potential record strength El Nino in 2026.

Last week, the Nino4 SSTA warmed too above the El Nino threshold. The Nino4 region is located on either side of the Dateline and the warming in this region is a southwestward expansion of surface warming associated with an intense marine heatwave off the West Coast of North America.